Gravitational Waves Reveal Lightest Black Hole Ever Observed (sciencemag.org) 44
sciencehabit shares a report from Science Magazine: Gravitational wave detectors have spotted a cosmic collision in which a giant black hole swallowed up a mystery object seemingly too heavy to be a neutron star, but too light to be a black hole. Weighing in at 2.6 times the mass of the Sun, the object falls into a hypothetical "mass gap," a desert between the heaviest neutron star and the lightest black hole that some theories predict -- suggesting the gap doesn't exist and that those theories need to be amended. The data come from physicists working with the Laser Interferometer Gravitational-Wave Observatory (LIGO), a pair of detectors in Louisiana and Washington state, and Virgo, a similar detector in Italy.
It's the 2.6-solar-mass object that raises eyebrows because it falls squarely in the mass gap, says Vicky Kalogera, an astrophysicist and LIGO team member from Northwestern University. "Now, for the first time, we have seen such an object," she says. By sensing only the gravitational waves from the collision, LIGO and Virgo cannot tell for sure what the object is, she says. But nuclear physics suggests a neutron star heavier than about 2.2 solar masses cannot support its own weight, so the object is "almost certainly" a black hole, Miller says. The study has been published in The Astrophysical Journal Letters.
It's the 2.6-solar-mass object that raises eyebrows because it falls squarely in the mass gap, says Vicky Kalogera, an astrophysicist and LIGO team member from Northwestern University. "Now, for the first time, we have seen such an object," she says. By sensing only the gravitational waves from the collision, LIGO and Virgo cannot tell for sure what the object is, she says. But nuclear physics suggests a neutron star heavier than about 2.2 solar masses cannot support its own weight, so the object is "almost certainly" a black hole, Miller says. The study has been published in The Astrophysical Journal Letters.
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You had the chance to make a great yo mamma joke and you blew it.
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Stupid Brain (Score:2)
Comment removed (Score:5, Informative)
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What does adding a neutron to the largest possible neuteon star do other than start a black hole?
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Current understanding is that black holes can't exist less than 5 solar masses, it takes that much mass to overcome the quark degeneracy pressure to collapse to a singularity.
The mass gap is that neutron stars can't exist above 2.5 solar masses because the strong nuclear effect collapses at that point. Quantum stars have been theorized to fill the gap, essentially above 2.5 solar masses the star collapses further to quantum particles, this would hold with quark degeneracy pressure until the star had enough
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Ok that was what I was missing. I thought once neutrons collapsed, that was it, and not that there is, or might be, one more stage.
Re: Alternate article (Score:2)
Could it be a supercritical state that spontaneously collapses?
Interesting point (Score:3)
That's an interesting point. It may be that stars can't exist in stable state in this mass gap, but can exist in a metastable state in the same way that liquid water at atmospheric pressure can exist at temperatures well over 100C. Just don't depend on it staying that way for long.
Re:Quark Stars (Score:5, Informative)
This is one of the questions LIGO is trying to answer.
They are also trying to investigate the interior of neutron stars to see if there are quark layers or perhaps a strange quark core.
The current director of LIGO Hanford (Michael Landry) is a specialist in strange quarks, having had the chance to chat with him (super nice guy btw), he is very excited to be seeking the answers to these very questions.
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if it can't be a neutron star because one that massive would collapse into a black hole, then why is it too light to BE a black hole? It's not like it gets heavier when it collapses into a black hole?
I've also read that spinning neutron stars can fudge a little bit on the weight limit due to their spin fighting off a little bit of the collapse, but they didn't provide any hard numbers on just how much heavier it could get as a result of high spin. It looked like it was implying only a very small differenc
Re:Quark Stars (Score:5, Interesting)
The reason for a mass gap is that there's a gap in the mechanisms for creating heavy neutron stars and light black holes. The processes of stellar collapse that lead to each don't vary smoothly, so it's not clear how you'd get a stellar remnant in that particular range of masses.
If the thing is a light black hole then it suggests there are some subtleties about supernovae we don't understand (possibly most likely, least interesting possibility) or that you can get oddball objects produced by weird multi-star processes (accretion onto a neutron star, maybe a neutron star / white dwarf merger). If it's a heavy non-black hole then it's possibly something like a quark star, which would tell us interesting things about extreme nuclear physics.
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The subject you are quoting is the solution to the possible mass gap. Quantum stars have been suggested for a while now and it's possible that this 2.6 object might have been a such a quantum star.
Wikipedia has a good definition of this but as mass exceeds the neutron start limit there is theorized that a start might collapse further to sub-atomic particles, quarks, muons, etc. and that this quantum star might exist within this mass gap between neutron stars and singularities.
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As I understand it, sitting here in my chair-with-arms:
Spacetime has a maximum matter/energy density of x mass per cubic (or decahedric or more, by some theories) unit before the maths break down and we start seeing infinity signs.
A spinning body very near to that limit may impart enough angular momentum to prevent the matter from crossing that threshold, but as it slows spinning through micro-collisions and heat loss, it allows just enough mass to accumulate to exceed that limit, which starts a chain react
Just a very heavy rock? (Score:1)
(and I do mean heavy!) Surely there are other possibilities than just black holes and neutron stars. Presumably something in the signal eliminates stars and the like.
Re:Just a very heavy rock? (Score:5, Insightful)
Presumably something in the signal eliminates stars and the like.
Yes. To merge like that, the objects must be very small and dense. Black holes and neutron stars are the only known objects that fit. A black hole cannot collide with a star in the same way that an aircraft cannot collide with a cloud :-)
The very well tested theories do not allow anything else so dense, that we know of. Less strongly, theory says neutron stars of that mass are unstable, so it almost certainly is a black hole. There is no theoretical reason why black holes of that size cannot exist. We just don't know how they form, and have never seen one before.
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When was the first well accepted observation by a LIGO?
How can we be sure something even happened let alone that it was within this specified mass, or that the acceleration magnitude and direction was as expected to actually even separate mass from acceleration?
Seems just a bit thin to be refuting models with this data yet...
One confirmed formation mechanism (Score:3)
There is no theoretical reason why black holes of that size cannot exist. We just don't know how they form, and have never seen one before.
That's not entirely correct: LIGO has already observed the merger of two neutron stars to form a black hole in this mass range. So that's technically both an observation of one and how it was formed.
Of course, from what we know this has a low chance of happening and it might, therefore, be statistically unlikely to expect to see a subsequent merger involving one of these objects but we do at least have one confirmed formation mechanism.
From what I understand though there is no known reason why a supe
Re:Just a very heavy rock? (Score:4, Informative)
Not "some mass" (Score:3)
When some mass is larger than 1.4 solar masses
It's more specific than that: this applies to stars, not to all masses in general since it is the density that actually matters. Theoretically, you can create black holes with subatomic particle collisions which would have masses a tad under 1.4 times the mass of the sun. However, the energies required (in the absence of new physics) are extreme: about 15 orders of magnitude higher than the Large Hadron Collider.
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For masses larger than 1.4 solar masses you just have to wait until the type 1A supernova happens.
Small margin of error (Score:2)
It sounds nice if you claim that the mass 'falls squarely into the mass gap' but if the calculated mass is 20% higher then you have already bridged the mass gap.
It's a strong statement to claim that the mass was estimated with a smaller error margin than 20%. I'd challenge that first.
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Src: https://www.sciencedaily.com/r... [sciencedaily.com].
"Mass-gap" BHs come from neutron star mergers (Score:3)
TFA:
LIGO and Virgo have shown that it’s possible to form a low-mass black hole in a different way [from supernovas]. In August 2017, they spotted the merger of two neutron stars, which produced, presumably, a black hole of 2.7 solar masses.
Here's picture of a black hole.. (Score:1)
image_of_black_hole [meshpage.org]
It's sligghtly dark..
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image_of_black_hole [meshpage.org]
It's sligghtly dark..
Oh, no! I'm not getting caught by goatse again, not this little black duck.
Set a course, number one. (Score:2)
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And set photon torpedoes to "rinse".
But only if you've already been to here [krapschass.lu]. Or else, you'll have to rinse again...
Look? (Score:2)
I can't really begin to understand the details of this, but is it possible that we may have looked at the area this occurred in with a regular telescope? I mean, we can't see the black hole (except by lensing), but we might be able to see a star, if that's what it collided with - and now presumably there is no such star, which we should also be able to see. Likewise, if it's a black hole, then we can't see that either, so whilst not as dramatic, would add some weight (see what I did there?) to the argument
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"When the LIGO and Virgo scientists spotted this merger, they immediately sent out an alert to the astronomical community. Dozens of ground- and space-based telescopes followed up in search of light waves generated in the event, but none picked up any signals."
"According to the LIGO and Virgo scientists, the August 2019 event was not seen by light-based telescopes for a few possible reasons. First, this event was six times farther away tha
Hawking Radiation (Score:2)
Though, I guess it would be shining very brightly if that were the case.
Re:Hawking Radiation (Score:5, Interesting)
Not mentioned in TFA, but couldn't Hawking Radiation have weaned its mass from above the mass gap?
Hawking radiation for an object of 2.6 solar masses is so tiny, it actually can't lose mass at the current stage of the universe. At that mass, the black hole temperature is around 2.4x10^-8 K, which is far below the temperature of the CMB at 2.7 K. Basically, the black hole is gaining mass from the CMB, and will continue to do so until the universe expansion cools down the CMB temperature by many orders of magnitude.
Universe too Young (Score:4, Informative)
Evaporating? (Score:2)
Could it be a black hole that was so small it began evaporating?
And for the trolls and morons, "evaporation" is by Hawking radiation.
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The universe isn't old enough for any stellar remnant black hole to lose anything noticeable by evaporation, a 2 solar mass black hole will take about 8 times 10 to the 67th power years to evaporate.
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????? What on *earth* is someone as ignorant as you doing hanging out on slashdot?
Can't be a hard mass gap (Score:2)
I would think that there must be exceptions to any mass gap because surely the mass gap applies to the formation of the bodies... not their future evolution in the presence of added mass from companions or the like. So if a neutron star forms initially and mass is slowly trickled into it, can it not become a black hole through the back door rather than in its initial supernova? And be of whatever mass ends up exhausting the additional supply.